How to Paint Basement Cinder Block Walls

Paint cinder block walls with waterproof paint.

Painting basement cinder block walls keeps moisture at a minimum. Using a masonry or waterproof paint avoids the potential for mold and mildew development, which can result in health issues. The cinder blocks need proper preparation before painting to ensure the primer and paint adhere to the walls correctly.

Things You'll Need

• Water
• Dish detergent
• Buckets
• Soft-bristled brush
• Sponge
• Rubber gloves
• Rubber boots
• Goggles
• Muriatic acid
• Vacuum cleaner with sweep attachment
• Primer
• Paint brush or rollers
• Paint pans
• Waterproof paint

Instructions

1. Mix a solution of warm water and two squirts of dish detergent into a bucket. Dip a soft-bristled brush into the cleaning solution and scrub the cinder walls, removing dirt and grime embedded into the concrete. Rinse the walls after cleaning with warm water and a sponge and allow to dry completely.

2. Acid etch the cinder blocks before painting. Put on rubber gloves, boots and goggles. Add one part muriatic acid to three parts water in a bucket. Apply the acid mixture to the cinder block walls with a stiff-bristled brush. The muriatic acid bubbles on the concrete. Rinse the walls with a garden hose or a bucket of water and a sponge after the bubbling has ceased. Allow the cinder blocks to dry completely.

3. Vacuum the cinder block walls with a sweeper attachment after the walls have dried. The acid etching leaves white residue that needs removal before painting.

4. Apply primer to the cinder walls. Pour primer into a paint pan and roll onto a paint roller or paint brush. Wipe primer onto the cinder block walls using up and down strokes. Allow the primer to dry before applying the paint.

5. Pour waterproof paint into a clean paint pan. Roll paint onto the roller or paint brush and apply to the cinder walls. Paint the walls generously, making sure to get into tiny crevices of the cement. Allow to dry and apply a second coat. Cement is porous so you may need a third coat to achieve the desired color.

Tips & Warnings

• Open basement windows when applying primer and paint to basement walls. Run a fan for ventilation if there are no windows in the basement.

• You may need to wait 24 hours between applying the paint to the primer and between coats of paint if the basement is damp or during high humidity. Use a fan directed at the walls to speed up the drying process.

• Never pour water into muratic acid as you risk splashing the acid. Wear rubber gloves, rubber boots, goggles, long sleeves and pants when handling muratic acid to avoid burns. Make sure the basement is well ventilated because muriatic acid gives off toxic fumes.

References

• True Value Paint: Painting Concrete Walls